JPH02195955A - Implant and making thereof - Google Patents

Abstract

PURPOSE: To develop a soft tissue implant in a form of meniscus cartilage part replacement for a patient by providing a top layer and a bottom layer to hold a felt-type middle layer in between, and an elastic bonding material to coat each layer and to maintain it in a laminated form. CONSTITUTION: This implant 10 is used as a replacement for a semicircular cartilage part of a human knee, and the implant 10 is attached to the top of a tibia 11 and the bottom of a condole of a femur 14 of a patient. The implant 10 consists of a body 20, which has external line edges 22 and 23. The body 20 comprises a multiple-layer laminate, and the laminate consists of a bottom layer 30 of cloth, a first felt middle layer 31, a second felt middle layer 32, a top cloth layer 33, and so forth. Because an elastic bonding material 34 covers the bottom face 24 and the top face 25 of the body 20 and this bonding material 34 is held between facing surfaces of each of layers 30, 33 and is coated on each layer, each of layers adhere to form the section in a taper.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to soft tissue implants or grafts, and more particularly to meniscus cartilage replacement for patients.

[Prior Art] and [Problem to be Solved by the Invention] U.S. Patent No. 4,502.16 to Wall
The meniscus cartilage replacement for a patient disclosed in No. 1 consists of a fabric sheet coated with an elastic material, the lateral extension of which extends outward from the joint of the human body to the side of the tibia. It will be stopped. However, the replacement in the above US patent is thin and flat (two-dimensional), resulting in disadvantages in terms of anatomical shape.

U.S. Patent No. 4,344°193 granted to Kenney
The meniscus cartilage replacement disclosed in
It has a three-dimensional shape. However, the replacement of U.S. Pat. No. 4,344,193 simply consists of an unreinforced molded silicone rubber member.

Incidentally, although several other possible methods are briefly discussed, the figures in the Kenney patent show the sutures and thickened ends that hold the replacement in place in the joint.

The thickened end portion will be described in detail later.

U.S. Patent No. 3.87 awarded to Stub Stud
The artificial implant disclosed in No. 9,767 is designed for spinal disc replacement.

Homsey U.S. Patents 3,971,670 and 4
, 127,902 merely discloses an artificial tensioning member that is introduced into a hole within a bone and secured for use as a replacement ligament.

Cartilage replacement is not disclosed.

None of the specifications describes meniscus cartilage replacement that satisfies me.

[Purpose of the invention]

It is therefore an object and subject matter of the present invention to provide a soft tissue implant in the form of a meniscus cartilage replacement for a patient, which implant incorporates anatomically shaped woven and felt fibers into the natural meniscus cartilage. It is designed to be incorporated into the patient's adjacent tissue in a manner similar to that of a patient. The woven felt-like fibers are reinforced on the inside and have sufficient strength and durability. The coated top and bottom surfaces of the implant described above are capable of sliding against adjacent tissue of the patient.

The convex outer edge of this implant can receive the natural fibrous Ml tissue that has grown within the patient's body, allowing the implant to be fixed in a timely and natural manner to the patient's joint. I can do it. If desired, the implant can be securely anchored to the adjacent bone until the body's fibrous tissue grows out.

The object and subject matter of the present invention is to provide at least one top layer and a bottom layer of suitable shape with one felt-like intermediate layer in between;
This is accomplished by providing a soft tissue replacement implant, such as a meniscus cartilage replacement for a patient, that includes a resilient bond material coating the layers and holding them together in a laminate.

The middle layer is canted more narrowly than the top and bottom layers, but the side edges of each layer are commonly coincident.

The shape of the top layer is three-dimensional and has a wedge-shaped cross section. The fabric member is bonded to the thick edge of the final laminate and has pores so that the patient's tissue can grow inside and ultimately secure the implant in place. In addition, the method of manufacturing the implant includes coating each layer with an elastic bonding material, stacking the layers on top of each other, and then curing the elastic bonding material.

〔Example〕

FIG. 1 shows a soft tissue implant IO embodying the invention.
shows.

In its broadest sense, the present invention relates to human (or other mammalian)
The particular implant IO shown herein may be used as a replacement for the meniscus or half-moon of cartilage in the human knee, or may be implanted in other parts of the patient to facilitate understanding of the preferred embodiments of the present invention. It is being done as a thing. Although the present invention can easily be used for each of the lateral and medial meniscus cartilages, for illustration purposes, the specific example is limited to replacement for the medial meniscus cartilage.

Thus, as shown in FIG. 11, an implant 10 embodying the invention is attached to the top of a patient's tibia 11 and to the underside of the corresponding condyle of the greater bone 14.

The intermediate meniscus cartilage implant 10 has an anatomical shape, ie, a three-dimensional configuration that resembles the patient's natural intermediate meniscus cartilage.

More specifically, the implant IO has an overall C-shape (i.e., kidney bean shape) as shown in FIG. 1, and a wedge-shaped central cross-sectional shape as shown in FIG. ing.

The implant 10 consists of a body 20 which is separated from one end to the other. This body portion 20 has outline edges 22 and 2.
3, that is, it has a concave perimeter edge 22 and a convex perimeter edge 23 (see FIG. 1.6). The convex perimeter edge 23 defines the end 2 of the generally C-shaped body 20.
Define 1.

The concave and convex perimeter edges are in a facing configuration and spaced apart across the width of the generally C-shaped body 20. The bottom of this body 20 is flat (see Figure 6).
, the top surface is sloping, preferably slightly concavely curved. The central portion of the convex perimeter edge 23 is considerably thicker than the concave perimeter edge 22. For example, the central portion of the concave perimeter edge 23 can be as high as one quarter inch, while the concave perimeter edge is preferably a feather edge. The concave perimeter edge 23 stands substantially perpendicularly from the bottom surface 24 of the body 20 at least in its central portion. Since the concave perimeter edge 23 slopes from its thick center 26 towards the end 21 of the body 20 (as generally shown in FIG. 11), the concave perimeter edge 23 , taper substantially towards the beveled edge of the central portion 26 of the end portion 21 .

The body portion 20 (see FIG. 6) is made of a multilayer laminate. In the preferred embodiment shown, such a laminate comprises a bottom layer 30 (see FIG. 3.4) of woven cloth, successively stacked thereon at least one first felt intermediate layer 31, preferably It consists of a second felt intermediate layer 32, a top cloth layer 33, etc.

Typically, more than one felt layer is not required. A resilient bonding material 34 covers the bottom surface 24 and top surface 25 of the body 20, and the bonding material 34 is sandwiched between and coated on each layer of the laminate between the facing surfaces of each layer 30-33. The layers adhere to each other, thus providing the tapered cross-sectional shape described above.

As shown in FIGS. 3 and 6, the widths of layers 31-33 vary. The bottom fabric layer 30 has a significant width, measured between its convex and concave perimeter edges, resulting in an implant 10 having the shape shown in plan view. 11 of the first intermediate felt layer 31 is 1 of the bottom layer 30
1, and the width of the second intermediate layer 32 is slightly narrower than the intermediate felt layer 31. On the other hand, the edges of the bottom textile layer 30 are semi-circular, and the edges of the intermediate felt layers 31 and 32 are generally quite narrow and pointed, as is evident in the illustrated embodiment. Top fabric layer 33 is generally similar in shape and dimensions to bottom layer 30, only being slightly narrower in width.

As shown in FIG. 6 (and as indicated by the dashed lines in FIG. 3), each layer 30-32 is stacked on top of each other;
The central portions of these convex perimeter edges are stacked vertically, and each end and convex perimeter edge 2 are stepped inwardly. At least in part because of their slope, the ends and concave perimeter edges of top fabric layer 33 are desirably slightly separated from the corresponding edges of bottom fabric layer 30, as shown in FIGS. 3 and 6. It is stepped inward.

+1 of each layer is different, the ends of each layer and the concave perimeter edge are stepped, and the elastic bonding material 3
4 has initial fluidity, so that the cross-sectional shape of the implant 10 becomes wedge-shaped.

Porous tube 4, preferably made of knitted fibers
0 (see FIG. 9) can have any hollow cross-sectional shape, for example a circular cross-section. However, in the preferred embodiment shown, the tube 40 has a generally rectangular cross-section, with the four corners arranged in a curled configuration 41 evenly spaced circumferentially. The edges of the four side walls 42 are integrally connected. However, since the tube 40 is soft and pliable, its shape can be changed in any way. Because the tube is made from a porous material, fibrous tissue grows within the patient and enters the adjacent open meshes of the sidewalls 42 and curled corners 41, thus allowing the tube to remain adjacent to the patient, as described in more detail below. It is intertwined with the organization that does.

An elastic bonding material 43 attaches one side wall 42' (see FIG. 2.8.9) of the tube 40 to the relatively thick central portion of the convex perimeter edge 23 of the body 20. The tube 40 is symmetrically located along the convex perimeter edge 23, which is approximately 180-200 degrees arcuate. The end of the tube 40 is preferably trimmed at an angle, as shown at 44 in FIGS. 1 and 8, so that the trimmed open end 44 of the tube 40
approaches the end 21 of the body, lying substantially tangential to the curved convex perimeter edge 23 of this body. The ends of the tube 40 thus fit smoothly into the shape of the body near these ends 21.

Preferably, the woven fiber high tensile tape 50 (first .
2.10) extends loosely through the tube 40, the end of which extends well beyond the tube 40 and the body 20 for purposes described below.

Although other materials are possible, in the preferred embodiment shown, the following materials have been found to be desirable.

Thus, the woven bottom fabric layer 30 and the woven top fabric layer 33 are made by cutting fabric sheets of commercially available woven polyester (eg, Dacron trademark).

This woven Dacron cloth is relatively thin. In other words, it's only about as thick as paper. According to the invention, the woven polyester cloth piece used as a unit is of the type made for implantation in the field of cardiac pathology, for example a cardiac patch.

The felt layers 31 and 32 may also be made of a cloak-like polyester (e.g., Dacron or Teflon trademark) material, which is extremely soft and fluffy and has a rough, wool-like structure. are doing. Felt layers 31 and 32 have a JV several times that of woven fabric layers 30 and 33. The monolithic felt layer according to the present invention has a thickness of approximately one-sixteenth of an inch or slightly more before being coated.

Woven and felt fabrics as described above (30-33)
For example, each product number 019254.019
304.019306.019314.019316.
019324.019326 from Meadox, Inc., Oakland, New Jersey.

The tube 40 is also woven into a long tubular shape using polyester (eg, Dacron trademark) fibers approximately one-quarter inch in diameter. Use a suitable tube with product number 130-
10, available from Maid Sok, Oakland, New Jersey.

The tape 50 is also made of fibers of high tensile woven polyester (eg, Dacron®). In the illustrated embodiment, the width of the tape is about one-eighth of an inch and the tensile strength is about 150 Bond. A suitable tape is available from Meadox, Inc., Oakland, New Jersey, under product number 130-20.

The elastic bonding material employed is a polyurethane liquid used as a coating for bonding the above-mentioned components together, in which case the part to be coated is cured, meaning that the part is exposed to normal temperatures and humidity. The curing agent (dimetulasedimide) is removed by placing it in a special controlled environment. A polyurethane bonding material available under the trademark Surethane and available from Cardiac Control Systems, Inc. of Palm Coast, Fla., is also suitable.

The cured polyurethane forms a smooth layer that inhibits fiber ingrowth in the patient and prevents slipping and low friction conditions when coated with fluid within the joint. , which is close to the nature of the natural meniscus cartilage.

Although it is possible to vary the dimensions of the meniscus cartilage at will to suit the required cartilage to be replaced, for the particular intermediate meniscus cartilage constructed according to the present invention, the length of the body 20° (measured horizontally in Figure 1) is approximately 1/4 to 3 inches, with a maximum (measured along vertical section line n-n in Figure 1).
, about one-half inch, with an overall shape as shown in FIG.

A preferred method for manufacturing the implant 10 shown in FIG. 1 will be described below.

The woven fabric, cloak-like, generally C-shaped flat layers 30-33 are cut to the desired size and shape (depending on the size range, shape and type of body cartilage to be replaced). .

When the fabric bottom layer 30 is cut into pieces, the layer is coated with the elastic bonding material 34 at least once (preferably twice) and cured after each coat. Unless stated elsewhere below, the coated layers (along with the partial laminate formed as described below) lie flat during the curing time. This is because, after curing, the layer tries to regain its elasticity and assumes a certain form (curved or flat), which form is maintained throughout the curing time. Curing has been performed by conventional polyurethane curing methods.

This conventional curing method is performed in a conventional polyurethane curing chamber, the temperature and humidity of which are controlled in a conventional manner.

The top surface of the bottom layer 30 is then coated again with an elastic bonding material and the first felt layer 31 is placed thereon. The manner in which this is done is generally shown in dotted lines at the bottom of FIG. That is, the convex edges at the center of each layer are aligned in the vertical direction. The resulting initial laminate piece 30.31 is then cured.

An elastic bonding material is then coated onto the top surface of the felt layer 31 and the coated surface of the lower layer 30.

A felt intermediate layer 32 is then placed on top of the covering layer 31. The elastic bonding material of the resulting partially laminated pieces 30-32 is cured.

The elastic bonding material is then coated on both sides of the top layer 33 of the woven fabric, which
is held in a three-dimensional semicircular shape. This semicircular structure resembles part of a round bowl. That is, the concave perimeter edge 60 lies substantially in one plane, thus extending the central portion 61 of the convex perimeter edge 62 by the desired thickness of the central portion 26 of the convex perimeter edge 23 of the body 20. from the surface of the concave perimeter edge 60. This causes the ends of the coated top layer 33 to be pulled from a vertical flat position, indicated by dotted lines 63 in FIG. This is done by fixing with means such as a bottle 64. Thus, the ends 63 of the top layer 33
For example, it is fixed to a solid substrate such as a styrofoam board and subjected to a hardening action.

Once top layer 33 is cured, bin 64 is removed and layer 3
Even after removing 3 from the substrate 65, the deformed shape is maintained.

Preferably, a second coating of elastic bonding material is applied to the top layer 33 and cured again. During this second curing process, the top layer 33, now coated twice, is again tacked to the base +ff 165 with a pin 64 in the position shown in solid line in FIG.

This layer 33 is thus firmly fixed by the deformed bowl part shape.

Elastic bonding material 34 is then further coated onto the top surface of upper ferll 132, thus covering the exposed edges of coating layers 31 and 32. This distorted, three-dimensional bowl segment layer 33 is then placed over the coated lower layers 30-32 and subjected to a subsequent curing step. As a result, a laminate body 20 having an overall wedge-shaped cross section as shown in FIG. 6 is obtained.

The coating penetrates only a portion of the thickness of the felt layer, so the interior of the felt layer remains fluffy and flexible. That is, the finished implant is soft because the elastic bonding material has been largely excluded from within the finished implant.

Elastic bonding material is then further coated onto the convex perimeter edge 23 of the body 20 and the long side 42'' of the tube 40 with the trimmed end 44 is placed against it.The resulting structure is , hardened,
The tube 40 is firmly adhered to the body 20 in the configuration shown in FIGS. 1 and 2. Of course, the elastic bonding material 34 penetrates into the apertures in the knitted sidewall 42 of the tube 40 so that when the elastic bonding material cures against a conventional elastic rubber-like material, the knitted tube wall Bonding inside the 42゛ opening? 13 penetrates finely, thus fixing the tube 40 and the body 20 together.

Before the tube 40 is brought into contact with the elastic bonding material on the body 20, a tape 50 may be inserted into the trimmed tube 40 so that it protrudes from the end of the tube as shown in FIG. Once the tube 40 has been adhered to the body 20 as described above and the intervening elastic bonding material 34 has cured, the tape 50 is thereby held in place on the convex perimeter edge 23. As a practical matter, the elastic bonding material 34, before curing, extends far enough through the opposing tube wall 42° to contact a portion of the tape 50, thus making the tape 50
is attached to the end of the body 20. However, such end-to-end fixing is not always necessary, and tube 4
It is sufficient to have only the tape 50 in contact with the body 20 and to allow the tape 50 to extend freely into the tube 40 in the longitudinal direction.

As shown in FIG. 11, the implant 10 is inserted into the patient's body cartilage (in this example, the intermediate meniscus cartilage), is seated on the top of the tibia 11, and is inserted into the condyle of the upper large bone. I support 13. The grown body fibrous tissue then enters the openings in the knitted fibers of the tube 40, such as the top and bottom surfaces of the tube 40, particularly the lateral and outwardly facing surfaces 42'', and positions the implant 10 within the joint. Hold it firmly.However, when the joint bends normally, the tibia 11 and the condyles 1
3 slips at a normal level.

The exposed end of tape 50 can be utilized by the surgeon, if desired, to secure implant 10 in place during pain relief and fibrous tissue ingrowth. This procedure is carried out downwardly through the top of the tibia 11.
This is done by opening the angle hole 70 and letting it out from both sides (see Figure 11). Next, the exposed end of Qi 150 is
It is extended downwardly through the angled hole 70 and secured to the side of the tibia 11 using conventional surgical staples 71. Thus, relative movement between the tibia 11 and the condyle 13 facing the implant 10 is limited. If the surgeon determines that the exposed end of the tape 59 does not need to be used for fixation purposes, the exposed end protruding from the end of the tube 40 can simply be cut off.

During use, body fluids normally present within a patient's joint are removed from the polyurethane-coated, sealed bottom surface 2 of the implant 10.
4 and the top surface 25 are coated. These bottom and top surfaces correspond to the corresponding bottom and top surfaces of the intermediate meniscus cartilage of the human body, which are located in similar positions. The implant 10 thus interacts with the tibia 11 and condyle 13, which move relative to each other, like the intermediate meniscus cartilage of the human body, when the patient's joint is in motion.

[Brief explanation of the drawing]

1 is a view from the top of the convex outer circumferential edge of a meniscus cartilage implant according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view taken along line nn in FIG. 3 is an exploded view of the woven felt component of the implant shown in FIG. 1, and FIG. 4A is a portion of the woven fabric superimposed with the outer contour of the component of FIG. 4B is a top view of the sheet fabric shown in FIG. 4A; FIG. 5A is a top view of the sheet fabric shown in FIG. 4A; and FIG. 5A is a top view of the sheet fabric shown in FIG. FIG. 5 is an end view of the felt-like sheet shown in FIG. 5A; and FIG. 6 is a cross-sectional view of the fragment shown in FIG. 2 in an unfinished state. and FIG. 7 is a top view, shown in dashed lines, of the top fabric layer component of the implant shown flat in FIG. 1, with the component shown in solid lines twisted into a three-dimensional bowl-shaped segment. 8 is a top view of the tube of the implant of FIG. 1; and FIG. 9 is a fragmentary view of the end of the tube of FIG. 8 before trimming. FIG. 10 is a top view of the elongated tape selectively used in the implant shown in FIG. 2 is a schematic diagram showing the implant of FIG. 1 installed as a replacement for.

Claims (1)

[Scope of Claims] 1. A textile bottom layer; at least one felt intermediate layer placed on top of the bottom layer; a textile top layer placed on top of the at least one felt intermediate layer; covering each of the above layers; at least one elastic bonding material coating, wherein the bonding material is interposed between each layer and adheres them to form a laminate, each layer having an overall C-shape in plan view. The C-shaped body has concave perimeter edges spaced apart from each other in a direction transverse to the width of the C-shaped body, and a convex perimeter edge facing the concave perimeter edges, and the convex perimeter edges are formed on the C-shaped body as a whole. The width of the at least one felt interlayer defining the end portion is:
Narrower than that of each layer of the fabric top and bottom, the concave perimeter edges and ends are folded inside the corresponding concave perimeter edges and edges of each layer of the fabric top and bottom, and the body has a thin concave perimeter The central section from the edge to the rather thick convex perimeter edge is tapered, and the convex perimeter edge tapers and becomes thinner toward the end, and the body part is thus , a meniscus cartilage for a patient, characterized in that the cross-sectional shape of the central part is wedge-shaped, and the top layer of the fabric is three-dimensionally distorted, that is, the whole has a bowl shape. Soft tissue implants in the form of replacements. 2. An implant according to item 1 above, wherein the three-dimensional shape of the top layer is comparable to the shape obtained by slightly moving the mutually distant ends of a flexible flat C-shaped sheet towards each other. . 3. Implant according to item 1 above, wherein said layer is made of polyester fiber and said bonding material is made of polyurethane. 4. The implant according to item 1 above, wherein the thin concave perimeter edge is warped. 5. The felt layer is made of fluffy, irregular filament flexible material, and the coating is
Since the bonding substance penetrates only a part of the thickness of the felt layer, the central part of the felt layer remains fluffy and soft, and the bonding substance hardly penetrates into the finished implant, so the finished implant is soft. Implant according to paragraph 1 above. 6. A textile fabric bottom layer; at least one felt intermediate layer placed on top of the bottom layer; a woven fabric top layer placed on top of the at least one felt intermediate layer; at least one woven fabric top layer covered by each of the layers; an elastomeric bonding material coating comprising an elongated tube of woven fabric, the bonding material being interposed between each layer to adhere them together to form a laminate, the laminate having mutually separated ends; a perimeter edge extending between these ends, the body forming a wedge shape in a central cross section so that the central part of the perimeter edge is the thickest part, and extending toward each end. , the tube extends over the perimeter edge and is in contact with the perimeter edge on one side, with a layer of elastic bonding material interposed between the two, from the thickest central portion fairly close to the end. The sides of the tube are bonded to the perimeter edge, the elastic bonding material is bonded to the wedge and embedded within the textile material of the tube, and the hollow center portion of the tube is bonded end to end. The elastic bonding material does not penetrate into at least the opposite side of the tube, so that its fibrous material can interact with the eventual adjacent tissue growth within the patient's body. An intertwined, soft tissue implant in the form of a meniscus cartilage replacement for the patient. 7. includes a high tensile strength tape extending through said tube and projecting a significant length from its ends to form a pair of temporary bonding materials, the end means of said tape extending through said tube and projecting for a significant length from said ends thereof; holding the body and the attached tape in place until tissue ingrowth into the hole and tightly joins and intertwines with the opposite side of the tube; can be done,
Soft tissue implant according to paragraph 6 above. 8. The implant according to claim 7, wherein the body is substantially C-shaped in plan view, so that the peripheral edge and the tube adhered thereto are convexly curved. 9. An implant according to clause 8, wherein the end of the tube is trimmed at an angle so that it is substantially tangential near the end of the body to the convex perimeter edge of the body. 10. The overall C-shaped body also has a concave perimeter edge connecting the ends of this body, simultaneously forming a thin end with a wedge-shaped cross-section, and this concave perimeter has opposite edges. An implant according to claim 8, wherein the implant is of almost negligible thickness relative to the peripheral edge of the side and is glued to the tube. 11. The tube is made of knitted polyester,
Implant according to clause 7 above, wherein said tape is made of polyester. 12. (a) Flat and whole C of thin woven cloth and felt material
(b) coating the C-shaped woven fabric layer with an elastic bonding material and then curing the bonding material to form a bottom portion of the felt material; (c) forming at least one felt layer on said bottom layer;
layer by layer, coating at least one of the facing surfaces of the bottom layer and the layer of felt material with an elastic bonding material, the convex edge of each layer being bonded to the concave edge of the bottom layer of the felt material layer. the concave edges of the felt material layers are stacked such that the concave edges of
curing the laminate of layers; (d) coating a second flat overall C-shaped layer of thin woven fabric with an elastic bonding material and securing the ends of the woven fabric layer to each other and at a reduced distance to the substrate; ,
distorting the second fabric layer into a three-dimensional shape forming part of a bowl, and curing the second coated layer in the three-dimensional shape forming a part of the bowl to form a top layer; (e) at least one of the top surface of the intermediate laminate and the three-dimensional bowl segment shaped top layer;
coated with an elastic bonding material, the top layer is stacked with the top surfaces of the laminate, i.e., the convex edges of each side are stacked, with the concave edges of the top layer being located substantially close to the concave edges of the bottom layer; (f) a surface opposite the concave edge of the multilayer laminate;
coating at least one of the tubes of porous fabric with an elastic bonding material, compressing the opposing surfaces together, and then curing the resulting meniscus cartilage replacement. How to make cartilage replacement. 13. The manufacturing method according to item 12 above, including the step of inserting a high tensile strength tape through the tube and causing the end of the tape to protrude from the end of the tube before step (f). 14. The method of claim 12, comprising trimming the end of the tube at an angle substantially tangent to the end of the multilayer laminate. 15. The manufacturing method according to item 13 above, wherein each of the layers is made of polyester fiber, and the bonding material is made of polyurethane. 16. Passing the high tensile strength tape through the tube,
extending a considerable length from the end of the tube to form a pair of temporary fasteners, the ends of the tape being able to be introduced into a hole in the adjacent bone of the patient and firmly secured thereto; 15. A method according to paragraph 14, wherein means are provided to hold the body and mounting tape in place during tissue growth so that they can be interconnected with opposing sides of the tube. 17. The method according to paragraph 12 above, further comprising step (c) of paragraph 12 above, wherein at least a second layer of felt material is placed on the layer of felt material to form an intermediate laminate of at least three layers.